EP0141551A1 - Titanatpulver und Verfahren zu seiner Herstellung - Google Patents

Titanatpulver und Verfahren zu seiner Herstellung Download PDF

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EP0141551A1
EP0141551A1 EP84306926A EP84306926A EP0141551A1 EP 0141551 A1 EP0141551 A1 EP 0141551A1 EP 84306926 A EP84306926 A EP 84306926A EP 84306926 A EP84306926 A EP 84306926A EP 0141551 A1 EP0141551 A1 EP 0141551A1
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Prior art keywords
powder
barium
water
particle diameter
hydroxide
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French (fr)
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EP0141551B1 (de
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Fumio 325-Go Asahikasei-Shinjo Matushita
Kageyasu 523-Go Asahikasei-Shinjo Akashi
Satoshi Sekine
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Asahi Kasei Corp
Asahi Chemical Industry Co Ltd
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Asahi Chemical Industry Co Ltd
Asahi Kasei Kogyo KK
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Priority claimed from JP58189249A external-priority patent/JPS6081023A/ja
Priority claimed from JP58199173A external-priority patent/JPS6090825A/ja
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/003—Titanates
    • C01G23/006—Alkaline earth titanates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/46—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates
    • C04B35/462—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates
    • C04B35/465—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates based on alkaline earth metal titanates
    • C04B35/468—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates based on alkaline earth metal titanates based on barium titanates
    • C04B35/4682—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates based on alkaline earth metal titanates based on barium titanates based on BaTiO3 perovskite phase
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/46—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates
    • C04B35/462—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates
    • C04B35/465—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates based on alkaline earth metal titanates
    • C04B35/47—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates based on alkaline earth metal titanates based on strontium titanates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/60—Compounds characterised by their crystallite size
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/30—Particle morphology extending in three dimensions
    • C01P2004/32—Spheres
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/50—Agglomerated particles
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/51—Particles with a specific particle size distribution
    • C01P2004/52—Particles with a specific particle size distribution highly monodisperse size distribution
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/12—Surface area

Definitions

  • This invention relates to a novel powder consisting of barium titanate, strontium titanate or a solid solution thereof (hereunder the powder is referred to as the titanate powder) having a small particle diameter, a narrow particle size distribution and a substantially spherical shape, as well as to a process for producing the titanate powder.
  • the present invention further relates to the novel titanate powder which can be sintered at low temperatures.
  • the starting powder for the sintered body be fine, good in dispersion and uniform in particle diameter and shape.
  • Titanate powders which have large particle diameters and non-uniformity of particle diameter distribution and shape, have industrially been used. These powders require a high temperature, at least 1,300°C, in order to sinter them up to 90% in relative density.
  • the titanate powders which have a small particle diameter, have been synthesized. But they, not only being poor in dispersion but also being non-uniform in particle diameterjand shape, are difficult to pack uniformly, resulting in non-uniform sintering and causing variations in dimensional accuracy and physical property.
  • Titanates are now in wide use as a material for electronic parts such as condenser, PTC element, semiconductor and the like.
  • a titanate for example, in a multi-layer ceramic condenser
  • the fact that a temperature of 1,300°C or more is required for sintering the titanate necessitates the use of a high melting noble metal such as palladium, platinum or the like and causes an increase of electrode cost.
  • grains in the sintered body become larger owing to grain growth, and hence, the distance between electrodes cannot be shortened and a condenser of high capacity cannot be realized; and variations in dimensional accuracy and physical properties cause a reduced yield and an increased cost.
  • titanate powders have industrially been produced by the solid phase reaction method.
  • This solid phase reaction method is a method wherein barium salt (e.g. barium carbonate) or strontium salt (e.g. strontium carbonate) is mixed with titanium dioxide and they are reacted at a high temperature of 1,000°C or more to synthesize barium titanate or strontium titanate.
  • barium salt e.g. barium carbonate
  • strontium salt e.g. strontium carbonate
  • this method is disadvantageous in that sintering has already started at the time of powder production, and particle-particle bonding and particle growth have occurred, and essentially, this makes it difficult to produce a barium titanate powder or a strontium titanate powder having a very small and uniform particle diameter.
  • the oxalic acid method is a method wherein an oxalate is burnt at a temperature of 600°C or more to synthetize a titanate, and therefore, is close to the solid phase reaction method and tends to cause agglomeration of powder particles.
  • the alkoxide method is expensive in starting materials and has a problem in the industrial scale production.
  • the hydroxide method is not yet an established technique; however it employs a simple production process, is inexpensive in starting materials and produces a powder having a high sinterability.
  • Kubo et al. report in Kogyo Kagaku Zasshi, Vol. 71, No. 1 (1968) that they have produced barium titanate at a conversion of 100% by mechanically mixing hydrous titanium oxide having a water content of 95% by weight with barium hydroxide in a barium to titanium ratio of 2 to 3 and then heating the mixture to 100°C.
  • the barium titanate obtained by the Kubo et al. method has an angular shape very similar to the shape of hydrous titanium oxide, and therefore, its specific surface area is as large as 40.2 m 2 /g, agglomerates of particles appear and the particle diameter distribution is non-uniform.
  • the Kubo et al. method is superior in that it can synthesize barium titanate in a high yield at a low temperature of 100°C, but is not satisfactory in respect of particle shape, particle agglomeration, particle diameter distribution, etc.
  • Matsuoka et al. describe in the Report of Research Laboratory of Hydrothermal Chemistry of Kochi University, Vol. 2, No. 15 (1978) that they synthesized barium titanate by mixing titanium oxide with barium hydroxide so that the ratio of elemental barium to elemental titanium became 1.2 and then treating the mixture at 110° to 370°C in a stirring type autoclave.
  • titanium oxide of a relatively large particle diameter was used and therefore, in order to obtain a conversion of 100%, a high temperature and a high pressure (300°C and 85 atm. or more) were required and the particles of barium titanate produced were coarse.
  • Matsuoka et al. also point out in the report that the addition of water during the mixing of titanium oxide and barium hydroxide resulted in a reduction of conversion.
  • a titanate powder which can be uniformly sintered at a low temperature
  • the present inventors have conducted extensive research on the synthesis of a titanate powder having a very small and uniform particle diameter.
  • a novel titanate powder which has a very small and uniform particle diameter,-spherical shape, a small specific surface area, and substantially no agglomeration can be synthesized by reacting hydrous titanium oxide with barium hydroxide and/or strontium hydroxide in the presence of a relatively large quantity of water and, if necessary, calcining the reaction product at an appropriate temperature for completion of the reaction.
  • a powder consisting of barium titanate powder, strontium titanate powder or a solid solution thereof, characterized in that (a) the average particle diameter is 0.07 to 0.5 p, (b) the specific surface area measured is 20 m 2 /g or less and does not exceed 2.5 times the specific surface area calculated from the average particle diameter on the assumption that the powder particles be spherical, (c) the crystallite size calculated from the half-width of the peak of the X-ray diffraction pattern of the powder is 0.05 p or more, and (d) the shape is substantially spherical.
  • the present invention further provides a process for producing the above-mentioned powder, characterized by reacting hydrous titanium oxide with barium hydroxide and/or strontium hydroxide at a temperature ranging from 60°C to less than 110°C in the presence of 120 to 2,000 moles of water per mole of titanium.
  • Figs. 1 and 2 are scanning electron microphotographs of 13,000 and 50,000 magnifications, respectively, of the barium titanate synthesized in Example 1
  • Figs. 3 and 4 are scanning electron microphotographs of 13,000 and 50,000 magnifications, respectively, of the barium titanate powder synthesized in Example 2.
  • substantially spherical used in the present invention refers to a state as shown in scanning electron microphotographs of Figs. 1 to 4 in which the shape of each particle is close to sphere as a whole.
  • the particle diameter and shape of the titanate powder of the present invention can be measured by an observation through a scanning electron microscope (e.g. Scanning Electron Microscope Model S-430, manufactured by Hitachi, Ltd.).
  • a scanning electron microscope e.g. Scanning Electron Microscope Model S-430, manufactured by Hitachi, Ltd.
  • the titanate powder of the present invention has an average particle diameter ranging from 0.07 ⁇ to 0.5 ⁇ , but each particle thereof has substantially the same particle diameter, and the standard deviation is 1.5 or less.
  • the average particle diameter x determined from an observation through a scanning electron microscope and the standard deviation a are calculated according the following equations using the particle diameter x i of any one of the n particles which can be seen within the unit visual field, x i being obtained by measurement: wherein and n is preferably at least 1,000.
  • Each particle of the titanate powder of the present invention has a substantially spherical shape.
  • a value obtained by dividing the difference between the largest diameter and the smallest diameter by the largest diameter is 3/10 or less.
  • the dispersibility of powder can be determined by measuring the particle size distribution of the powder. Particle size distribution can easily be measured, for example, by the use of Micro Photo Sizer SKA-5,000 of S eishin Enterprise Co., Ltd.
  • the particle size distribution of barium titanate powder was measured by dispersing the powder in isopropyl alcohol, adding polyethylene glycol thereto as a dispersing agent, and subjecting the resulting dispersion to measurement of particle size distribution.
  • the average particle size determined from the particle size distribution measurement agrees approximately with the average particle diameter determined by the above-mentioned observation through a scanning electron microscope. Moreover, the particle size distribution is narrow and the standard deviation is 2.0 or less.
  • the average particle size x determined from the particle size distribution measured and the standard deviation a are calculated according to the following equations: wherein
  • x i is a particle size expressed by an arithmetical average of the largest and smallest diameters of the particles in the small measurement zone i;
  • v i is a fraction of the volume occupied by the particles in the measurement zone i; and
  • n is the number of the small measurement zone i.
  • the crystallite diameter can be determined by firstly measuring the half-width of the peak of an X-ray diffraction pattern for powder and then substituting the half-width for the ⁇ of Scherrer's equation.
  • L is a crystallite size
  • ⁇ is the wavelength of X-ray used
  • ⁇ is the half-width of the peak of an X-ray diffraction pattern
  • 0 is the diffraction angle of X-ray used
  • K is a constant, which is assumed to be 0.9 in the present invention.
  • the above half-width ⁇ is determined from the peak corrected by the use of a silicon crystal on the assumption that the shape of the peak of X-ray diffraction pattern for powder measured be the Cauchy profile.
  • the crystallite size, calculated according to the above equation, of the titanate powder of the present invention agrees approximately with the average particle diameter of the same powder determined by the above-mentioned observation through a scanning electron microscope. That is, approximately one particle consists of one to dozens of crystallites and the crystallite sizes actually measured are 0.05 p or more.
  • the specific surface area can be measured by means of a specific surface area analyzer of the gas adsorption type (e.g. Sorptomatic 1800, manufactured by Carlo Erba).
  • a specific surface area analyzer of the gas adsorption type e.g. Sorptomatic 1800, manufactured by Carlo Erba.
  • the specific surface area of the titanate powder of the present invention which area has actually measured does not exceed 2.5 times the specific surface area calculated from the average particle diameter of the titanate powder on the assumption that the particles of the powder have a true sphere shape.
  • the ratio of the specific surface area actually measured to the specific surface area calculated has a tendency of decreasing according as the specific surface area increases, and the specific surface area measured does not exceed 20 m 2 /g. Accordingly, the particle diameter obtained by back calculation from the specific surface area actually measured agrees approximately with the average particle diameter, and it can also be confirmed from this fact that the titanate powder of the present invention is spherical and of non-agglomerating nature.
  • the titanate powder of the present invention having the above-mentioned characteristics cannot be produced by any of the conventionally known methods described above, and can be produced only when the novel synthesis method described herein is used.
  • the process for the production of the titanate powder of the present invention is characterized by reacting anhydrous titanium oxide with barium hydroxide and/or strontium hydroxide, with stirring, at a temperature ranging from 60°C to less than 110°C in the presence of 120 to 2,000 moles of water per mole of titanium.
  • the reaction in the present process is greatly impaired by the presence of carbon dioxide. Accordingly, in carrying out the reaction, sufficient care must be taken to ensure that no carbon dioxide is present in the reaction system. Further, carbon dioxide must be removed, prior to the reaction, from all the reactants (hydrous titanium oxide, barium hydroxide and/or strontium hydroxide), the water used for dispersion and dilution of the reactants, etc.
  • the hydrous titanium oxide there may be used at least one compound selected from orthotitanic acid, metatitanic acid and titanium oxide.
  • Orthotitanic acid is most preferred in view of its high reactivity. They can be used in the form of solid or gel. Orthotitanic acid can easily be obtained by alkali-treating a chloride, a sulfate, an oxalate, etc. of titanium. The use of the chloride is preferred. Metatitanic acid and titanium dioxide are easily obtained by heating orthotitanic acid because the constitution water which orthotitanic acid has is gradually lost by this heating.
  • Both the barium hydroxide and the strontium hydroxide used in the present invention are white solids ordinarily containing water. They may be used as they are or in the form of an aqueous solution. Since both barium hydroxide and strontium hydroxide easily react with carbon dioxide in air to form the respective carbonates, they must be purified, prior to their use in the reaction, to remove the respective carbonates, and the purified hydroxides must be handled carefully to prevent their recontact with carbon dioxide. The purification of barium hydroxide and strontium hydroxide can be conducted by a known method.
  • the use of a relatively large quantity of water in the present invention results in the following effects: Since the reaction of hydrous titanium oxide with barium hydroxide and/or strontium hydroxide proceeds mildly, the powder formed has a large crystallite diameter and is free from micro cracks, small in specific surface area and substantially free from agglomeration. Further, since fluidization is possible during the reaction, the powder formed is substantially spherical in particle shape and uniform in particle diameter distribution.
  • the mixing method is conducted in the presence of water and this has effects of making the shape of particles substantially spherical and the particle diameter distribution uniform.
  • the mixing method may be carried out in'a known manner such as stirring, vibration, rotation, ball mill treatment or the like.
  • the reaction time is preferably 30 min or more for completing the reaction as much as possible, though it is not critical.
  • the reaction mixture can be calcined for completion of the reaction.
  • the calcining temperature is preferably 1,000°C or less. If the clacining temperature is more than 1,000°C, sintering begins to occur, causing powder particles to be firmly bonded to one another and resulting in particle growth, which impairs the characteristics of the present invention.
  • the quantity of water used is preferably 120 to 2,000 moles, more preferably 200 to 1,000 moles, per mole of titanium.
  • the ratio of barium and/or strontium to titanium in the titanate powder produced is greatly affected by the quantity of water used in the reaction. That is, when the quantity of water is in the range of 200 to 1,000 moles per mole of titanium, the ratio of barium and/or strontium to titanium is about 1 and, as the water quantity deviates from the above range, the ratio becomes smaller. When the water quantity is less than 120 moles or more than 2,000 moles per mole of titanium, the ratio is too small.
  • the fluidity of the starting material mixture reduces, and when the water quantity is less than 120 moles, the fluidity is lost and this not only makes difficult the production of a powder having a spherical shape and a uniform particle diameter but also increases the reactivity between 5 hydrous titanium oxide and barium hydroxide and/or strontium hydroxide, including the formation of a powder having small crystallites, pores, a large specific surface area and accordingly a high agglomeration tendency.
  • the water quantity exceeds 10,000 moles per mole of titanium, the concentration of reactants in the reaction system is reduced, whereby the reactivity is decreased and it is practically difficult to carry out the reaction.
  • the quantity of barium hydroxide and/or strontium hydroxide is preferably 1.3 to 5.0 moles, more preferably 1.5 to 3.5 moles, per mole of the hydrous titanium oxide.
  • the quantity is in the range of 1.5 to 3.5 moles, a complete reaction takes place and the ratio of barium and/or strontium to titanium in the titanate formed becomes 1.
  • the ratio becomes less than 1 and, when the quantity is less than 1.3 moles or more than 5.0 moles, the ratio becomes too small and the titanate powder obtained cannot be used in practice.
  • the reaction is effected at a temperature of 60°C to less than 110°C.
  • the reason therefor is that when the reaction temperature is less than 60°C, the rate of the reaction between hydrous titanium oxide and barium hydroxide and/or strontium hydroxide is too slow to be practical.
  • the temperature is 110°C or more, the reaction becomes a hydrothermal reaction, which increases the cost of reaction apparatus, causes particle growth in the particles formed, and makes it difficult to produce a powder having a very small and uniform particle diameter.
  • the barium titanate and/or the strontium titanate thus obtained is water-washed, filtered, dried and, optionally, calcined at an appropriate temperature in a conventional manner, followed by washing with a weak acid, water-washing, filtration and drying in a conventional manner.
  • the titanate powder of the present invention is small in particle diameter and uniform in particle diameter distribution. Accordingly, this powder has a high reactivity with various doping agents and is useful as a starting material for not only multi-layer ceramic condensers but also various other condensers, PTC elements, semiconductors, etc.
  • the sintering temperature for the titanate powder of the present invention is 100° to 200°C lower than that for conventional titanate powders. This can reduce the energy cost of sintering and further, when the baking of electrode is conducted concurrently with the sintering of condenser as in multi-layer ceramic condensers, can significantly reduce the cost of electrode.
  • the titanate powder of the present invention may be a mixture or solid solution with other chemical elements.
  • the reactor contents were heated at 100°C for 4 hr by means of an oil bath to effect reaction. After completion of the reaction, the reaction mixture was allowed to stand for about 5 min. The supernatant was removed and 3 liters of hot water was added to the residue. After stirring and washing, the residue was filtered. This operation of washing and filtration was repeated three times (a total of 9 liters of hot water was used for washing of the residue). Then, the residue was washed with 0.5 liter of 1 N acetic acid and filtered. Further, an operation of washing with pure water and filtration was repeated three times.
  • the product was found to be a cubic system barium titanate powder consisting of uniform, substantially spherical particles with an average particle diameter of 0.21 p and a standard deviation of 1.28 and having a specific surface area of 8.0 m 2 /g and a crystallite size of 945 A.
  • the specific surface area of 8.0 m 2 /g the average particle diameter calculated on the assumption that all the particles of the powder obtained be spherical was 0.12 p and this agreed approximately with the average particle diameter measured from the observation through a scanning electron microscope.
  • the particle size distribution of the barium powder obtained was measured. It gave an average particle size of 0.32 p and a standard deviation of 1.78, whereby the powder was found to be good in dispersion.
  • This barium titanate powder had a barium to titanium ratio of 1.004. Further, there were conducted an observation through a scanning electron microscope, a measurement of specific surface area and an X-ray diffractometry. From these, the powder was found to be cubic system barium titanate powder having an average particle diameter of 0.28 p, a standard deviation of 1.41, a specific surface area of 7.7 m 2 /g and a crystallite size of o 1101 A. With respect to the specific surface area of 7.7 m 2 /g, the average particle diameter calculated on the assumption that all the particles of the powder obtained be spherical was 0.13 p and this agreed approximately with the average particle diameter measured from the observation through a scanning electron microscope. Further, the particle size distribution of the barium titanate powder obtained was measured, to find that the powder had an average particle size of 0.38 p and a standard deviation of 1.82, and a good dispersibility.
  • the reactor contents were heated 100°C for 4 hr by means of an oil bath to effect reaction. After completion of the reaction, the reaction mixture was treated in the same manner as in Example 1, to obtain a barium titanate powder.
  • This powder had a barium to titanium ratio of 0.994 which slightly deviated from 1.
  • a measurement of specific surface area and an X-ray diffractometry it was found that the powder had an average particle diameter of 0.31 ⁇ , a specific surface area of 5.5 m /g and a crystallite size of 1280 A.
  • the measurement of a particle size distribution gave an average particle size of 0.56 ⁇ and a standard deviation of 1.96.
  • the particles of this powder were substantially spherical in shape but slightly angular.
  • This powder was subjected to an observation through a scanning electron microscope, a measurement of specific surface area and an X-ray diffractometry. As a result, the powder was found to be a cubic system strontium titanate powder having an average particle diameter of 1.5 ⁇ , a specific surface area of 8.4 m 2 /g, a crystallite size of 1028 A and a uniform and substantially spherical shape.
  • the powder was a cubic system solid solution of barium titanate and strontium titanate having an average particle diameter of 0.20 ⁇ , a standard deviation of 1.31, a specific surface area of 7.4 m 2 /g and a uniform and substantially spherical shape. From the measurement of particle size distribution, the powder had an average particle size of 0.30 ⁇ , a standard deviation of 1.80, and a good dispersibility.

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EP84306926A 1983-10-12 1984-10-10 Titanatpulver und Verfahren zu seiner Herstellung Expired EP0141551B1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP189249/83 1983-10-12
JP58189249A JPS6081023A (ja) 1983-10-12 1983-10-12 チタン酸バリウム粉末
JP58199173A JPS6090825A (ja) 1983-10-26 1983-10-26 チタン酸バリウムまたはチタン酸ストロンチウムの製造方法
JP199173/83 1983-10-26

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EP0212935A2 (de) * 1985-08-12 1987-03-04 Montedison S.p.A. Barium- und Strontiumtitanate und Verfahren zu deren Herstellung
GB2190076A (en) * 1986-05-05 1987-11-11 Cabot Corp Barium titanate coforms
EP0250085A2 (de) * 1986-06-16 1987-12-23 Corning Glass Works Bariumtitanat-Pulver mit uniformer Teilchengrösse und Verfahren zu seiner Herstellung
FR2601352A1 (fr) * 1986-07-14 1988-01-15 Cabot Corp Procede de production d'une poudre de titanate d'un cation divalent et procede de production d'une coforme a base de perovskite d'un cation divalent.
US4829033A (en) * 1986-05-05 1989-05-09 Cabot Corporation Barium titanate powders
EP0318111A2 (de) * 1987-11-25 1989-05-31 Philips Patentverwaltung GmbH Verfahren zur Herstellung von Bariumtitanat in Pulverform
US4863883A (en) * 1986-05-05 1989-09-05 Cabot Corporation Doped BaTiO3 based compositions
EP0439620A1 (de) * 1989-08-21 1991-08-07 Tayca Corporation Verfahren zur herstellung von pulverförmigen perovskiteverbindungen
EP0532114A1 (de) * 1991-09-13 1993-03-17 Philips Patentverwaltung GmbH Verfahren zur Herstellung wässeriger keramischer Suspensionen und Verwendung dieser Suspensionen
EP0346962B1 (de) * 1988-06-13 1993-05-12 SOLVAY (Société Anonyme) Verfahren zur Herstellung von Barium- und/oder Strontiumtitanatkristallen
EP0739019A1 (de) * 1994-10-19 1996-10-23 TDK Corporation Keramischer mehrschicht-chipkondensator
EP1148030A1 (de) * 1998-12-11 2001-10-24 Showa Denko Kabushiki Kaisha Titan enthaltendes oxid vom prerovskittyp
US9212066B2 (en) 2008-11-04 2015-12-15 Sachtleben Pigments Oy Process of preparing titanates

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US5242674A (en) * 1988-10-27 1993-09-07 E. I. Du Pont De Nemours And Company Process for preparing crystalline mixed metal oxides
US5445806A (en) * 1989-08-21 1995-08-29 Tayca Corporation Process for preparing fine powder of perovskite-type compound
IT1270828B (it) * 1993-09-03 1997-05-13 Chon Int Co Ltd Processo per la sintesi di polveri ceramiche cristalline di composti di perovskite
US5962551A (en) * 1997-01-31 1999-10-05 Kubota Corporation Powder of titanium compounds
EP1013608A4 (de) * 1998-05-20 2007-11-07 Toho Titanium Co Ltd Bariumtitanat pulver
PT1017625E (pt) * 1998-07-01 2002-12-31 Cabot Corp Processo hidrotermico para o fabrico de pos de titanato de bario
US6893623B2 (en) * 1998-12-11 2005-05-17 Showa Denko Kabushiki Kaisha Perovskite titanium-type composite oxide particle and production process thereof
US7030165B2 (en) * 1999-05-26 2006-04-18 Showa Denko Kabushiki Kaisha Perovskite titanium-type composite oxide particle and production process thereof
KR20020037038A (ko) * 1999-08-23 2002-05-17 마싸 앤 피네간 규산염 기재의 소결 보조제 및 소결 방법
US6264912B1 (en) * 1999-09-10 2001-07-24 Ut-Battelle, Llc Methods for producing monodispersed particles of barium titanate
US6733740B1 (en) 2000-10-12 2004-05-11 Cabot Corporation Production of dielectric particles
US6656590B2 (en) 2001-01-10 2003-12-02 Cabot Corporation Coated barium titanate-based particles and process
US6673274B2 (en) 2001-04-11 2004-01-06 Cabot Corporation Dielectric compositions and methods to form the same
US20030059366A1 (en) * 2001-09-21 2003-03-27 Cabot Corporation Dispersible barium titanate-based particles and methods of forming the same
US20030215606A1 (en) * 2002-05-17 2003-11-20 Clancy Donald J. Dispersible dielectric particles and methods of forming the same
US20040052721A1 (en) * 2002-09-13 2004-03-18 Kerchner Jeffrey A. Dielectric particles having passivated surfaces and methods of forming same
US20040121153A1 (en) * 2002-12-20 2004-06-24 Sridhar Venigalla High tetragonality barium titanate-based compositions and methods of forming the same
KR101158953B1 (ko) * 2005-02-25 2012-06-21 사까이가가꾸고오교가부시끼가이샤 조성물의 제조 방법
KR100633723B1 (ko) * 2005-08-04 2006-10-13 한화석유화학 주식회사 티탄산바륨의 제조방법
CN102674426B (zh) * 2012-05-21 2014-05-28 贵州红星发展股份有限公司 一种碳酸钡的制备方法及其制得的产品
WO2015152237A1 (ja) * 2014-03-31 2015-10-08 戸田工業株式会社 チタン酸ストロンチウム微粒子粉末及びその製造方法

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FR2009156A1 (de) * 1968-05-22 1970-01-30 Grace W R Ltd
US3725539A (en) * 1971-04-28 1973-04-03 Dow Chemical Co Preparation of alkaline earth metal titanate
US4061583A (en) * 1974-03-13 1977-12-06 Murata Manufacturing Co., Ltd. Preparation of titanates
DE2804104A1 (de) * 1977-01-31 1978-08-03 Sterling Drug Inc Verfahren zur herstellung einer dichten polykristallinen keramik
DE2707229A1 (de) * 1977-02-19 1978-08-24 Bayer Ag Herstellung von zink- und erdalkalititanaten
EP0104002A1 (de) * 1982-08-25 1984-03-28 Sony Corporation Verfahren zur Herstellung von feinem Metalltitanatpulver

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0212935A3 (de) * 1985-08-12 1989-03-08 Montedison S.p.A. Barium- und Strontiumtitanate und Verfahren zu deren Herstellung
US4755373A (en) * 1985-08-12 1988-07-05 Montedison S.P.A. Titanates in the form of spherical particles and process for preparing the same
EP0212935A2 (de) * 1985-08-12 1987-03-04 Montedison S.p.A. Barium- und Strontiumtitanate und Verfahren zu deren Herstellung
GB2190076A (en) * 1986-05-05 1987-11-11 Cabot Corp Barium titanate coforms
GB2190076B (en) * 1986-05-05 1990-12-05 Cabot Corp Barium titanate coforms
US4863883A (en) * 1986-05-05 1989-09-05 Cabot Corporation Doped BaTiO3 based compositions
US4829033A (en) * 1986-05-05 1989-05-09 Cabot Corporation Barium titanate powders
US4764493A (en) * 1986-06-16 1988-08-16 Corning Glass Works Method for the production of mono-size powders of barium titanate
EP0250085A2 (de) * 1986-06-16 1987-12-23 Corning Glass Works Bariumtitanat-Pulver mit uniformer Teilchengrösse und Verfahren zu seiner Herstellung
EP0250085A3 (de) * 1986-06-16 1988-11-23 Corning Glass Works Bariumtitanat-Pulver mit uniformer Teilchengrösse und Verfahren zu seiner Herstellung
GB2193713A (en) * 1986-07-14 1988-02-17 Cabot Corp Preparation of perovskite-type compounds
US4832939A (en) * 1986-07-14 1989-05-23 Cabot Corporation Barium titanate based dielectric compositions
FR2601352A1 (fr) * 1986-07-14 1988-01-15 Cabot Corp Procede de production d'une poudre de titanate d'un cation divalent et procede de production d'une coforme a base de perovskite d'un cation divalent.
GB2193713B (en) * 1986-07-14 1990-12-05 Cabot Corp Method of producing perovskite-type compounds.
EP0318111A2 (de) * 1987-11-25 1989-05-31 Philips Patentverwaltung GmbH Verfahren zur Herstellung von Bariumtitanat in Pulverform
EP0318111A3 (en) * 1987-11-25 1990-06-27 Philips Patentverwaltung Gmbh Process for the preparation of barium titanate in powder form
EP0346962B1 (de) * 1988-06-13 1993-05-12 SOLVAY (Société Anonyme) Verfahren zur Herstellung von Barium- und/oder Strontiumtitanatkristallen
EP0439620A1 (de) * 1989-08-21 1991-08-07 Tayca Corporation Verfahren zur herstellung von pulverförmigen perovskiteverbindungen
EP0439620A4 (en) * 1989-08-21 1992-10-21 Tayca Corporation Method of producing pulverized perovskite compound
EP0532114A1 (de) * 1991-09-13 1993-03-17 Philips Patentverwaltung GmbH Verfahren zur Herstellung wässeriger keramischer Suspensionen und Verwendung dieser Suspensionen
EP0739019A1 (de) * 1994-10-19 1996-10-23 TDK Corporation Keramischer mehrschicht-chipkondensator
EP0739019A4 (de) * 1994-10-19 1997-09-24 Tdk Corp Keramischer mehrschicht-chipkondensator
EP1391441A2 (de) * 1994-10-19 2004-02-25 TDK Corporation Keramischer Mehrschicht-Chipkondensator
EP1391441A3 (de) * 1994-10-19 2004-03-03 TDK Corporation Keramischer Mehrschicht-Chipkondensator
EP1148030A1 (de) * 1998-12-11 2001-10-24 Showa Denko Kabushiki Kaisha Titan enthaltendes oxid vom prerovskittyp
EP1148030A4 (de) * 1998-12-11 2008-11-19 Showa Denko Kk Titan enthaltendes oxid vom prerovskittyp
US9212066B2 (en) 2008-11-04 2015-12-15 Sachtleben Pigments Oy Process of preparing titanates

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US4898843A (en) 1990-02-06
DE3469161D1 (en) 1988-03-10
EP0141551B1 (de) 1988-02-03

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